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2006 27th IEEE International Real-Time Systems Symposium (RTSS'06) (2006)
Rio de Janeiro, Brazil
Dec. 5, 2006 to Dec. 8, 2006
ISSN: 1052-8725
ISBN: 0-7695-2761-2
pp: 35-46
Filip Pizlo , Purdue University
Jan Vitek , Purdue University
Memory management is a critical issue for correctness and performance of hard-real time systems. Java environments usually incorporate high-throughput garbage collection algorithms, but these algorithms can induce pause times in excess of 100 milliseconds. This is not acceptable for a real-time system. Two approaches for remedying this problem are being investigated. The pause times can be bounded with a real-time garbage collector; or a means to program around the collector entirely can be provided, as is done in the Real-time Specification for Java with its Scoped Memory interface. <p>This paper presents the first side-by-side empirical evaluation of the impact of memory management regimes on realistic realtime applications. We present usability arguments as well as a detailed performance comparison of scoped memory and real-time garbage collection. Experience with medium sized systems suggests that while programming with Scoped Memory is error prone, it provides substantially better throughput. We have observed a throughput reduction of up to 37% and, in the worst-case, an 80% latency penalty for real-time garbage collection.</p>

F. Pizlo and J. Vitek, "An Emprical Evaluation of Memory Management Alternatives for Real-Time Java," 2006 27th IEEE International Real-Time Systems Symposium (RTSS'06)(RTSS), Rio de Janeiro, Brazil, 2006, pp. 35-46.
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